In the contact spring arrangement disclosed in German Pat. No. 1,213,917, an essential portion of the pull exerted by the armature is stored in a double contact spring. Accordingly, practically no excitation energy is required to provide the contact force. In the known arrangement, an actuating nipple is disposed between the free ends of a bifurcated spring which has the same flexibility in both directions of its actuation. It is necessary that the contact clearance is smaller than the travelling distance of the armature by the path of travel required by the spring in either direction of actuation. It is furthermore disadvantageous that the bifurcated spring ends exhibit the same flexibility at the opening as at the closing of the contact couple.
In view of this problem, German Auslegeschrift No. 2,454,967 suggests an arrangement in which the contact couple is positively and forcibly opened, whereas the closing of the contact couple is done solely by pre-tensioning the contact spring. However, this arrangement allows only a small proportion of the pull provided by the armature to be stored in the contact spring.
It is an object of the present invention to provide a contact spring arrangement for a polarized relay which not only stores an essential portion of the permanent-magnetic pull exerted by the armature in a contact spring as the contact force, but also ensures a positive and forced opening of the contact couple with a contact clearance which is not reduced by any contact spring bending.
It is a further object of the present invention to provide a contact arrangement as set forth above, which is easy to manufacture and assemble from a minimum of structural components.